1. Field of the Invention
The present invention relates to an apparatus for manufacturing and a method for manufacturing a semiconductor device, and more particularly to a semiconductor device manufacturing apparatus and method for the purpose of forming, using a thermal CVD (chemical vapor deposition) method to form on a substrate a metallic film such as a film of copper or aluminum, a high dielectric coefficient layer such as a layer of titanium oxide strontium, and a ferroelectric film such as BST or TZT.
2. Description of the Related Art
In general, in fabricating a wire (a so-called damascene copper wire) by burying copper in a trench of a wiring pattern, a thermal CYD apparatus is used to deposit copper onto the substrate. FIG. 6 shows a general view of a thermal CVD apparatus in the past.
As shown in FIG. 9, a thermal CVD apparatus in the past has a hollow vacuum chamber 60, a vacuum pump 61 such as a turbomolecular pump for the purpose of exhausting the inside of the vacuum chamber 60 to a vacuum condition, a substrate holder 62, provided within the vacuum chamber 60, which holds a substrate W, a vaporizer 63 which atomizes the copper to be deposited on the substrate W as the raw gas, and a feed port 64 for the purpose of supplying the raw gas from the vaporizer 63 to within the vacuum chamber 60.
The substrate holder 62 has a substrate heating mechanism which is capable of controlling the temperature of the substrate W to within the range from 100° C. to 400° C. When depositing copper, the temperature is controlled to approximately 200° C.
Next, the method of depositing a copper film for the purpose of forming a copper wire using a thermal CVD apparatus of the past will be described. First, a trench is formed in the region in which a wire is to be formed on the silicon oxide film of the semiconductor substrate W.
Next, the above-noted substrate W is supported on top of the substrate holder 62 of the thermal CVD apparatus. The inside of the vacuum chamber 60 is brought to a vacuum condition beforehand by the vacuum pump 61.
Next, the substrate heating mechanism of the substrate holder 62 is caused to operate, so as to heat the substrate to a prescribed temperature. Simultaneously with this action, the Cu(hfac) (tmvs) raw gas, which has been vaporized by the vaporizer 63 is supplied to the supply port 64, together with a hydrogen carrier gas, and a copper film of a prescribed thickness is deposited onto the substrate W.
Then, using a CMP (chemical mechanical polishing) method, the deposited copper film is polished, so that copper remains only within the trench, thereby forming the copper wire.
In the Japanese Examined Patent Publication(KOKOKU) No. 1-19467 and the Japanese Unexamined Patent Publication (KOKAI)No. 2-119125 and in the Japanese Unexamined Patent Publications (KOKAI) Nos. 3-97871 and 3-257099, there is technology disclosed directed to the application of a voltage to a substrate holder that holds a substrate in a plasma CVD apparatus.
The major reaction of the above-described copper deposition reaction is chiefly the disproportionate reaction2Cu+1(hfac)(tmvs)−>Cu0+Cu+2(hfac)2+2(tmvs).
The rate of this reaction is established by the absorption of the 2 Cu+1 (hfac) molecules at the deposition surface and the movement of charge and removal of reaction products.
The driving forces of these rate-determining reactions are such things as the thermal energy according to the temperature of the substrate surface, and the amount of raw gas that is supplied, and it is difficult to improve the rate of reaction by means of these quantities.
The above-noted disproportionate reaction is, in principle, a reversible reaction, and it is thought that there is a limit to the control of the direction of the reaction by means of isotropic heat.
In formation of a copper wire using a thermal CVD apparatus of the past, in order to improve coverage it was necessary to lower the substrate temperature, which causes the rate of copper deposition to become slow (for example, 20 nm/minute). As a result, the time for fabrication of the semiconductor device becomes long, this resulting in a drop in productivity.
In the method of the past, because it was not possible to control the crystal orientation in the film that was formed, it was difficult to deposit a film having good quality with polarity alignment.
Additionally, in order to improve the reliability of the copper wires, it is necessary to control the grain growth in the copper film. With the method of the past, however, it was difficult to control grain growth.
In the plasma CVD apparatus technology that was disclosed in the above-noted Japanese Patent Publications, a bias voltage is applied to the substrate, and ions such as argon are allowed to collide with the surface of the substrate, the purpose being to impure the film surface purity and step coverage, and improve the flatness of the film surface, this being intrinsically different from the technology of the present invention, which uses an electrostatic action or the action of an electrical current.
Accordingly, it is an object of the present invention to solve the problems noted above, and to provide an apparatus and method for manufacturing a semiconductor device, whereby it is possible to promote the deposition of a film and to control the rate of film deposition, the crystal orientation, and the growth of grains.